Deceleration fuel flow and emission control for internal combustion engines

ABSTRACT

A control for the idling carbureted mixture of fuel and air of a vehicle-propelling internal combustion engine to reduce the fuel to air ratio when the vehicle is decelerating and is coupled to the engine. Engine intake manifold pressure and throttle valve setting govern the control which preferably leans the mixture sufficiently so it is not combustible in the engine.

Adair DECELERATION FUEL FLOW AND EMISSION CONTROL FOR INTERNAL 11113,823,699 1451 July 16, 1974 FOREIGN PATENTS OR APPLICATIONS 223,75810/1924 Great Britain.. l23/l 19 DB COMBUSTION ENGINES 1,217,948 1/1971Great Britain 123/97 B Inventor: Paul F. Adair Miami France B 1,179,7653/1961 Germany 23/97 B [73] Assignee: Aerodex, Incorporated, M1am1, Fla.I

[22] Filed: Oct. 20, 1972 Primary Examiner-Wendell E.-Burns' [211 pp No:299,460 Attorney, Agent, 0r FtrmCushman, Darby &

Cushman 1 [52] US. Cl 123/119 DB, 123/97 B, 123/124 R 4 I 51 1111.01.F02m 23/04 [571 AB a Field of arch l23/97 B, 124 R, 119 DB A control forthe idling carbureted mixture of fuel and r air of a vehicle propellinginternal combustion engine References Clted to reduce the fuel to airratio when the vehicle is de- UNITED STATES PATENTS celerating and iscoupled to the engine. Engine intake 2 439 57 4/19 Mallory 123/97 Bmanifold pressure and throttle valve setting govern the 2:443:562 6/1948Hilger et al. .L 123/97 B Centre! which Preferably leans the mixturesufficiently 2,453,125 ll/l948 Flint 123/97 B so it is not combustiblein the engine, 2,957,463 lO/l960 Schnabel 123/97 B 3,677,526 7/1972Perlot 125/97 B 4 l 2 Drawmg Flgms 0 Z 4/ L I4 7 2 r32 K I $0 W T 'm 625 #5 ill ll. .2 Z //fi f6 54 11% //Z A /fl/ 65 w aa 54/ a2 DECELERATIONFUEL FLOW AND EMISSION CONTROL FOR INTERNAL COMBUSTION ENGINESBACKGROUND OF THE INVENTION This invention relates to an arrangement forreducing the normal fuel to air ratio of the idle carbureted mixture ofa vehicle-propelling internal combustion engine during deceleration ofthe vehicle when it is coupled to, and to some extent driving, theengine. More especially, this invention relates to an improvedarrangement of the foregoing type for reducing the idle fuel to airratio in-response to predetermined negative intake manifold pressure. Bynegative pressure is meant pressure below atmospheric.

During normal operation of a conventional automobile propelled by aninternal combustion engine, the engine intake manifold vacuum, when theengine is idling with no appreciable load, will be around 19 inches ofmercury. When the engine is driving the vehicle the manifold. vacuumwill vary between and 19 inches of mercury, i.e., between about 19inches when the engine is idling to about 0 inches when the engine is infast acceleration. When the vehicle is rapidly decelerated, however, andthe engine remains connected to the driving wheels so that the engine isbeing driven to some extent by the vehicle, the manifold vacuum may riseto as much as 21 to 28 inches of mercury, depending upon the speed ofthe vehicle and the rate of deceleration.

During such deceleration, the higher manifold vacuum draws an abovenormal amount of the fuel air mixture through the idling duct into theengine. The abnorma] amount of fuel being thus used during decelerationis wasted. Moreover, since the engine is developing power from the fueland air mixture being drawn thereinto through the idle jet by the highermanifold vacuum, the engine is not being used to its full capacity toretard or brake the vehicle, so that the vehicle brakes must be usedtoan unnecessary extent to decelerate the vehicle.

Accordingly, it is an object of this invention to provide an improvedarrangement which will greatly reduce the fuel to air ratio, preferablybelow that necessary to support combustion, of the idle fuel and airmixture of a vehicle-impelling internal combustion engine duringdeceleration of the vehicle when the vehicle wheels are connected to theengine.

It is another object of this invention to provide an improvedarrangement of the foregoing type which will reduce fuel consumption,will decrease exhaust and smoke emissions, and will decrease brake wearof a vehicle driven by an internal combustion engine.

It is another object of this invention to provide an improvedarrangement of the type described that is readily adapted to be attachedto a conventional internal combustion engine which drives a conventionalvehicle.

Other objects and advantages of the invention will become apparent fromthe following description and accompanying drawing.

DESCRIPTION or THE DRAWING FIG. 1 is a schematic fragmentary sectionalview showing the application of this invention to a conventionalinternal combustion engine.

FIG.2 is an enlarged fragmentary view of a portion of FIG. 1.

DETAILED DESCRIPTION OF THE INVENTION Referring now to the drawing,there is shown a conventional downflow carburetor barrel 10 for conduct-7 ing a carbureted mixture of fuel, usually gasoline, and

-20 of the idle duct 18 is controlled by .an adjustable needle valve(not shown).

In the application of this invention to a standard type carburetor, asabove described, the conventional idle needle valve is replaced by anadjustable needle valve 22 of substantially the same construction buthaving a longitudinal duct 24 therein open at its outer end andterminating at its inner end in one or more radial orifices 26 whichopen into the idle duct 18 upstream of the outlet port 20. A conduit 28,e.g., a flexible hose,

has one end thereof connected to the outer end of the needle valve 22,in communication with itsduct 24, and the other end connected to a valvedevice 30. The latter 30 is arranged to communicate the needle valveduct 24, and consequently the idle duct 18, with the atmosphere to thusgreatly decrease the fuel to air ratio of the idle mixture admitted tothe engine manifold 12 under certain conditions. Preferably this ratiois decreased to such an extent that the mixture will not supportcombustion. The valve device 30 is arranged to be responsive to bothmanifold pressure and the position of the throttle valve 14 in such away that when the throttle valve is closed and the manifold vacuumexceeds a predetermined amount, such as normal idle manifold vacuum, theidle duct 18 is in communication with the atmosphere and the idlemixture is leaned as aforesaid.

The valve device 30includes a housing 32, preferably in two parts 34 and36, having an interior valve chamber 38 provided with one or more airinlet ports 40, in the housing part 34, communicating with ,theatmosphere. The chamber 38 also is provided with at least one outletport 42 in the housing part 34 having a valve seat 44 at its inner endnormally closed by a valve disc 46 guided for reciprocation by a pin 48coaxially fixed thereto and sliding in a bore 50 in the housing part 34.The outer end of the outlet port 42 is provided with an appropriatefitting 52 to which the conduit 28 is connected. It will be seen thatwhen the disc 46 is unseated the inlet ports 40 are in unobstructedcommunication with the outlet port 42.

The valve disc 46 is normally urged against its seat 44 by a coilcompression spring 54 interposed between a nut 56, threaded onto acentral stud 58 on the disc opposite the pin 48, and an enlarged innerhead 60 on an adjustment screw 62 engaged in and extending through atapped opening 64 in the wall of the housing part 36. The screw 62 issealed to the housing part36 by an O- ring 66 disposed in acircumferential groove in the enlarged head 60 and engaged with thesmooth wall of an interior cylindrical countersink 68 for the opening64.

A lock nut 70 preferably is threaded onto the outer end of the screw 62.

The housing 32 also is provided with an interior pressure chamber 72having a common wall with the valve chamber 38 formed by a pressureresponsive diaphragm 74. The central portion of the diaphragm 74 isclamped in sealing engagement with the rear of the valve disc 46 by anenlarged washer 76 beneath the nut 56, while the periphery of thedisphragm is clamped between the two parts 34 and 36 of the valvehousing 32.

The pressure chamber 72 is connected to the engine intake manifold 12 bya conduit 78, e.g., a flexible hose, having one end thereof connected toan appropriate fitting 80 on the intake manifold and the other endthereof connected toxa fitting 82 on the valve housing part 36. Thefitting 82 communicates with a housing port 84 provided, on its innerend, with a valve seat 86 normally engaged by the pointed end of acylindrical valve member 88 reciprocal in a'housing bore 90. The valvemember 88 is provided with a plurality of longitudinal grooves 92,terminating at their rearward end at a reduced extension 94 providing anannular space 96 communicating at all times with a port 98 opening tothe pressure chamber 72. The other end of the housing bore 90communicates with atmosphere by a reduced bore 100 in the housing part34 and an aligned opening 102 in the periphery of the diaphragm 74. Whenthe valve member 88 is seated against its seat 86, pressure chamber 72communicates with atmosphere via port 98, annular space 96, opening 102,and bore 100. The communication is interrupted, however, when valvemember 88 is pulled off its seat 86 and its rear end seats against themarginal edges of the diaphragm 74 surrounding the opening 102.

The arrangement is such that the manifold vacuum normally retains thevalve member 88 seated against its seat 86. If the valve member 88 ismoved off its seat 86, however, as later descirbed, the manifold vacuumwill be communicated to the pressure chamber 72. via the conduit 78, theport 84, the longitudinal grooves 92, the annular space 96, and'the port98. At the same time the rear end of the valve member 88 seats againstthe marginal edges of the diaphragm 74 about the opening 102 to seal offthe space 96 from atmosphere. When, as aforesaid, such vacuum exceeds apredetermined amount, normally 19 inches of mercury, atmosphericpressure in the valve chamber 38 will move the diaphragm 74 toward thepressure chamber 72 against the action of the spring 54 and unseat thevalve disc 46. Manifestly, the spring force can be adjusted, by thescrew 62, to enable the valve disc 46 to be unseated by any selectedpredetermined manifold vacuum.

The valve member 88 is connected to the throttle valve 14 by anyappropriate mechanical arrangement, such as a wire or nyloncord 104having one end connected to the rear end of the valve member 88 and theother end to a lever 106 on'an outer end of the throttle valve shaft 16.The arrangement is such that when the throttle valve I4 is closed (openis'shown in the drawings) the lever 106 and wire or nylon cord 104 pullthe valve member 88 off its seat 86 and against the marginal edges ofthe diaphragm 74 about the opening 102, and so communicates the manifoldvacuum with the pressure chamber 72. In the event that the vehicledriven by the engine decelerates, with the throttle valve 14 closed, tosuch an extent as to increase the manifold vacuum above a normal idlevacuum, e.g. about 19 inches of mercury, the valve disc 46'will unseatand thus communicate the carburetor idle duct 18 with the atmosphere ata location slightly upstream of the idle duct outlet port 20. Thiscommunication will, of course,greatly decrease the fuel to air ratio ofthe mixture being drawninto the engine manifold 12 through the idle duct18. Preferably the ratio is reduced to the extent that the mixture willnot be combustible in the engine. This will, in turn, decrease the fuelconsumption of the engine and consequently reduce exhaust and smokeemissions therefrom during such deceleration. Further, since the fuelsupply to the engine will be reduced the power developed by the enginewill also be reduced and preferably none developed, so the engine willhave greater drag resistance to slow the vehicle. Such greater enginedrag resistance will result in less necessity for application of thevehicle brakes and thus decrease wear on the latter.

It readily will be seen that the foregoing arrangement can bemanufactured in separate components for application to conventionalinternal combustion engines of conventional vehicles. The pressureresponsive valve device 30 can be constructed as a single unit, whilethe usual idle needle valve of the carburetor need only be replaced bythe tubular needle valve 22 illustrated in the drawings. The only othermodification necessary is that of providing a fitting in the engineintake manifold 12 for connection of the conduit 78. Frequently,however, a suitable fitting already is installed on engine intakemanifolds of conventional automobiles.

- Instead of replacing the standard idling needle valve of thecarburetor with the tubular needle valve 22 shown in the drawings, thecarburetor could be modified by tapping into the idle duct 18 atlocation above the needle valve and providing a fixture 118, as shown indotted lines, at this point for connection of the conduit 28. Further,in the event that the carburetor has more than one barrel, the valvechamber 38 can be provided with another outlet port 110 terminating inaninner seat engageable by the valve disc 46, and such port can beprovided with a fixture 112 for connection of another conduit thereto tobe connecected to the other barrel of the carburetor in exactly the samemanner as illustrated for the barrel 10. It further will be realizedthat the entire arrangement can be manufactured integrally with acarburetor, instead of being manufactured as an attachment. There aresome carburetor designs wherein the idle discharge port 20 is a fixedorifice and idle mixture is changed by an adjustable air bleed into idleduct 18. Attachment of valve device 30 to a carburetor of this type anduse of the hollow special design adjustable needle valve 22 will work inthe same manner for this type carburetor as for the one illustrated inFIG. 1.

It thus will be seen that the objects of this invention have been fullyand effectively accomplished. It will be realized, however, that thespecific embodiment shown and described is susceptible to modificationwithout What is claimed is: '7 V A g I 1. In a vehicle-propellinginternal combustion engine having a duct for admitting a carburetedmixture of air and fuel toan intake manifold, a throttle valve in saidduct, and an idle duct by-passing said valve, the combination of an idlemixture control comprising:

self-contained separate component means connected by passageway means tosaid manifold and to said idle duct and including means responsive to apredetermined negative pressure in said manifold for communicating saididle duct with the atmosphere to decrease the flow of fuel therethroughand therefor decrease the ratio of fuel to air in the mixture admittedtherefrom to said manifold and valve means controlling communicationbetween said responsive means and said manifold; and mechanical meansconnected to said valve means and to said throttle valve for openingsaid valve means when said throttle valve is closed.

2. The control defined in claim 1 including an adjustable needle valvecontrolling the outlet of the idle duct, said needle valve having a ducttherein terminating in an outlet upstream of said ilde duct outlet, andconduit means communicating said needle valve duct with the pressureresponsive means.

3. The control defined in claim 1 in which the pressure responsive meansincludes valve means, adjustable means urging'said valve means to closedposition, and diaphragm means having one side thereof exposed toatmospheric pressure and the other side thereof exposable to manifoldpressure for urging said valve means to open position.

4. The control defined in claim 1 in which the ratio of fuel to air inthe mixture admitted from the idle duct is descreased to the extentwhere the mixture is not ge u tib s in h is s-v

1. In a vehicle-propelling internal combustion engine having a duct foradmitting a carbureted mixture of air and fuel to an intake manifold, athrottle valve in said duct, and an idle duct by-passing said valve, thecombination of an idle mixture control comprising: self-containedseparate component means connected by passageway means to said manifoldand to said idle duct and including means responsive to a predeterminednegative pressure in said manifold for communicating said idle duct withthe atmosphere to decrease the flow of fuel therethrough and therefordecrease the ratio of fuel to air in the mixture admitted therefrom tosaid manifold and valve means controlling communication between saidresponsive means and said manifold; and mechanical means connected tosaid valve means and to said throttle valve for opening said valve meanswhen said throttle valve is closed.
 2. The control defined in claim 1including an adjustable needle valve controlling the outlet of the idleduct, said needle valve having a duct therein terminating in an outletupstream of said ilde duct outlet, and conduit means communicating saidneedle valve duct with the pressure responsive means.
 3. The controldefined in claim 1 in which the pressure responsive means includes valvemeans, adjustable means urging said valve means to closed position, anddiaphragm means having one side thereof exposed to atmospheric pressureand The other side thereof exposable to manifold pressure for urgingsaid valve means to open position.
 4. The control defined in claim 1 inwhich the ratio of fuel to air in the mixture admitted from the idleduct is descreased to the extent where the mixture is not combustible inthe engine.